心内直视手术中急性血液稀释对大剂量芬太尼药代动力学的影响

Effects of acute normovolemic hemodilution on pharmacokinetics of high dose fentanyl in open heart surgery

目的 研究心内直视手术中急性血液稀释自体输血对大剂量芬太尼药代动力学的影响。方法 随机选择二尖瓣置换术患者 2 0例 ,分为急性血液稀释组和对照组 ,每组各 10例。芬太尼60μg/ kg一次静脉注射后均抽取 2 4小时桡动脉血标本。应用 GC- MS检测血浆芬太尼浓度 ,3 P87软件包计算药代动力学参数。结果 芬太尼药代动力学符合开放性三室模型 ,在急性血液稀释自体输血组比对照组其 t1 /2 α和 t1 /2 β分别延长 6倍和 2倍 ( P<0 .0 1)。Vc和 Vd分别增加 1.5倍和 2 .5倍 ,两组的 Cl没有明显差异 ( P>0 .0 5 )。结论 心内直视手术中急性血液稀释对大剂量芬太尼药代动力有明显的影响 ,分布容积增大 。

Objective To study the effects of acute normovolemic hemodilution on the phar macokinetics of high dose fentanyl undergoing open heart surgery.Methods Twenty patients sched uled for elective MVR were randomly allocated to undergoing acute hemodilution (n=10) or not re ceiving it as control(n=10). Blood samples from radial artery following a bolus injection of fentanyl 60μg/kg were collected to determine the plasma fentanyl concentration by gas chromatography mass spectrum method. The pharmacokinetic parameters were calculated with 3P87 computer program. Results Pharmacokinetics of fentanyl could be described by triexponential equation corresponding to a three compartment open model. As compared with the control values,the plasma fentanyl concen trations decreased markedly t 1/2 β prolonged significantly (440.6min vs 213.7min,P<0.01), Vc, Vd and t 1/2 α increased by 1.5, 2.5 and 6 times respectively (P<0.05 0.01) in the hemodilution patients . In contrast, Cl was similar between the two groups (P>0.05). Conclusion Acute normovolemic hemodilution in open heart surgery can influence the pharmcokinetics of fentanyl through increasing the volume of distribution and prolonging the elimination.